Machines for grinding the ends of coiled springs and other articles



July 10, 1956 MACHINES FOR GRINDING THE ENDS OF COILED 5 Sheets-Sheet 1 Filed Jan. 21, 1954 ALAN Pay W/m'ELAm INVENTOR BY W 11W ATTORNEY! uly 10. 1956 A. R. WHITELAW 2,753,667

MACHINES FOR GRINDING THE ENDS OF comm SPRINGS AND OTHER ARTICLES Filed Jan. 21, 1954 s Sheets-Sheet 2 ALAN Ror WHITELAW mvs- TOR

BY -r ATTORNEYS A. R. WHITELAW MACHINES FOR GRINDING THE ENDS OF COILED July 10, 1956 SPRINGS AND OTHER ARTICLES 3 Sheets-Sheet 5 Filed Jan. 21, 1954 Tfl-AL/ mvenron BY m1 M ATTORNEY MACHINES FOR GRINDING THE ENDS F COILED SPRINGS AND OTHER ARTICLES Alan Roy Whitelaw, North Brighton, Melbourne Australia Application January 21, 1954, Serial No. 405,479

2 Claims. (Cl. 51-118) This invention relates to machines for grinding the ends of coiled springs and other articles, but particularly for grinding the ends of coiled compression springs, after they have been wound, in order to provide fiat end surfaces for seating on the parts upon which the springs are intended to bear; the said machines being of the kind comprising two spaced-apart grinding-wheels adapted for rotation and having opposed grinding faces between which the springs or other articles to be ground are passed in succession, while mounted in pockets in a rotating or other moving feed carrier, so that opposite ends of the articles are ground by the respective grinding-wheels.

As the grinding usually or frequently extends substantially around the full circumference of the end coil of a spring, and the free extremity of the spring has to be reduced to a feather edge, a considerable amount of metal, depending on the gauge of the wire and the diameter of the spring, may have to be removed. In known machines of the kind referred to, the grinding generally has to be completed by giving the springs several passes between the grinding-wheels, necessitating frequent stopping and re-setting of the machine, and delay in the completion of the finished product.

The principal object of the present invention is to provide, in a machine of the kind referred to, an improved form and disposition of the grinding-wheels whereby the full grinding of the ends of the springs or other articles may be completed during a single pass of the articles between the wheels;

Another object is to permit the springs or other articles to be discharged immediately after the full grinding has been completed, without its being necessary for the articles to pass idly over a non-effective grinding surface, so that risk of the springs or other articles jamming in their pockets in the carrier, after they have been reduced in length by the grinding, is obviated.

A further object is to provide improved grindingwheels and an improved grinding-wheel mounting, which can be readily adapted to an existing machine of the kind referred to, so as to enable the above advantages to be obtained, and the faces of which can be dressed by any usual straight-line-motion dressing tool.

According to the invention, a machine of the kind referred to, for grinding the ends of coiled compression springs and other articles, is provided with two grindingwheels having opposed spaced-apart faces of convex conical form between which a rotatable or other movable feed carrier can move so as to cause articles mounted therein to travel in succession with opposite ends in grinding contact with the respective faces, said grindingwheels being mounted with their axes of rotation inclined to one another so that the conical faces progressively approach one another from a tapered receiving entrance at one side to a substantiallyparallel relation at the opposite side, the carrier being so located in relation to the grinding-wheels that the articles therein are caused to travel across the faces of the wheels fromvsaid entrance side to the point where the faces arein substantially nited States Patent 0 parallel relation. The articles may be discharged in succession from the last-named point.

Figure l of the accompanying drawings is a side elevation of a grinding-machine in accordance with the present invention, one of the two grinding-wheels and its guard being shown in section.

Figure 2 is a front elevation of the machine with the guard of the upper grinding wheel in section to show the said wheel in elevation.

Figure 3 is a horizontal section on line III-III, Figure 1, showing the work carrier disc in plan, but with the work-pieces to be ground omitted.

Figure 4 is a diagrammatic sectional view through the two grinding wheels of the machine, without the work carrier disc, in order to show clearly the shape and disposition of the said wheels.

Figure 5 is a fragmentary cross-section through the grinding-wheels and work carrier disc taken on a plane represented by line V-V, Figure 3, but on a larger scale than Figure 3.

Figure 6 is a diagrammatic side elevation of the grinding wheels with the work carrier disc shown in section corresponding to an arcuate line passing through the work pockets in said disc, in order to illustrate the progressive grinding action on the work-pieces as they travel from one side of the wheels to the other.

Figure 7 is a view similar to part of Figure 3 but showing a modified disposition of the work carrier in relation to the grinding-wheels.

Referring to the said drawings, which show a convenient embodiment of the invention in connection with a machine for grinding the ends of coiled compression springs, during a single pass of the springs, the machine comprises a frame 1 supporting a vertical spindle 2 driven by a motor 3 through a worm reduction gear and chain drive, the reduction gear comprising a worm 4 on the motor spindle meshing with a worm-wheel 5, and the chain drive comprising a sprocket 6 on the shaft of wormwheel 5, connected by a chain 7 to a sprocket 8 on the lower end of spindle 2. The latter carries at its upper end a rotating horizontal carrier disc 9 having therein a circular concentric series of spaced-apart pockets or apertures 10 in which a set of springs 11 can be located and held in vertical positions so that their opposite ends project, respectively, from top and bottom faces of the disc. In Figures 1 and 2 only two springs 11 are indicated and in Figure 3 the springs are omitted. Beneath the disc 9 is a plate 12 fixed to a boss 13 on the top of the frame 1, the said plate serving to support the springs 11 outside the area of the grinding wheels, but having in its edge a gap 14 (Figure 3) located above the upper open end of a depending spring-delivery chute 15, and also being gapped at 16 corresponding to the area of the grinding wheels overlapped by said disc 9, as hereinafter described.

To one side of the spindle 2 of the carrier-disc 9 two circular upper and lower grinding-wheels 17, 18, are secured on separate driving shafts 19, 20, each driven in the same direction by an electric motor 21, 22, respectively, said wheels 17, 18, having their faces opposed to one another and being spaced apart in a vertical direction to form between them a horizontally extending space 23.

The grinding wheels 17, 18, are so located in relation to the carrier disc 9 that an outer portion of said disc is positioned in the space 23 between the wheels midway between the opposed faces of the wheels, so that the springs 11 mounted in the disc are successively carried between the wheels from one side to the other, the locus of travel of each spring being an arcuate path eccentric to the circumference of the Wheels and being, in the example illustrated, on the far side (considered from the disc axis) of the grinding-wheel centers. As already mentioned, the fixed plate 12 thatsupports the springs 11 is gapped at 16 so that it does not extend into the space between the grinding-wheels.

Guards 24,25, are fixed to the casings of motors 21, 22, to protect the respective wheels 17, 13, and each of the opposed faces of the two said wheels has its outer portion of a flat convex conical form of small angle (about 2/2%, for example), as indicated at 26, the circular center of each wheel being recessed at 27. The axes of the shafts 19, '26 carrying the wheels are inclined relatively to one another, so that atone point the two faces of the wheels are in parallel relation, as shown at the right-hand side of Figures 4 and 5, to form a parailehsided space at 28 (Figure 4); and from that point the said faces diverge circumferentially to form at the opposite side of the wheels a comparatively wide tapering 2) (Figure 4) having a maximum depth and taper at a point which is diametrically opposite to the point where the faces are parallel.

The desired inclination of the shafts 19, it}, is obtained by mounting the driving motors 21, 22, respectively, upon carrier plates 30, 31, pivoted at 32., 33, to slides 34, 35, which are vertically adjustable upon a fixed guide standard 36 by means of screws 37, 38, the said plates 3%, 31, being fixed, after adjustment, by clamping devices 39, 40.

The carrier-disc 9 is of such a diameter and has its shaft 2 so located that, as it rotates in the direction of the arrow marked on Figure 3, each spring 11 in succession is caused to enter the tapering space 29 between the wheels at a point in the circumference which is substantialiy at the point of the maximum depth of the space between the wheels, and to travel in an arcuate path between the opposed faces of the wheels 17, 18, with its ends in grinding contact with said faces, and to leave the said space exactly at the point on the circumference of the wheels where the opposed faces are parallel, namely, when it reaches the space 28. Each spring, as it approaches the entrance space 29, is guided into the said space by means of a deflector plate 41 conveniently supported by the upper wheel guard 24.

As each spring 11 travels from the relatively wide tapering inlet space 29 and across the faces of the Wheels to the point where the faces are parallel, it is compelled to move through a progressively narrowing space and is thus progressively ground on its ends, so that by the time it reaches the point where the faces are parallel, the ends have been ground truly parallel and to the desired extent during a single pass.

As each spring reaches the'edgcs of the grinding Wheels at the point 28 where the faces are parallel, it is delivered on to the plate 12 and then falls through the gap 14 in said plate into the chute 15, successive springs in the carrier disc following into the chute one after another.

In the modification represented in Figure 7, the construction and operation of the machine and its grinding wheels is intended to be the same as described above in connection with Figures 1 to 6, but the shaft 2' carrying the disc 9 with pockets is located so that the locus of travel of the workpieces between the grinding wheels (of which the lower wheel 18 is shown in Figure 7) is situated on the near side of the grinding-Wheel centers (considered from the disc shaft 2), thereby giving a shorter grinding path.

The provision,.in the improved machine, of the conicalfaced grinding-wheels having their axes of rotation inclined to one another causes the rate of end feed on the springs (that is, the rate of closure or contraction of the space between the opposed grinding faces) to be more rapid in the early part of the grinding cycle on each spring, andto become progressively less rapid towards thepoint where the wheelfaces are substantially parallel. This features of "a'progressively-decreasing endfeed rate enables conditions desirable for economical grinding to beobtaihed, since 'itallows the'grindingof each springintheinitial part .of the grinding cycle to be carried out at the maximum rate suitable (that is the greatest rate consistent with "the avoidance of undesirable conditions such as overheating), followed, in the later part of the cycle, by progressively less vigorous grinding ol' the springs to allow any distortion of the spring-axes, which may have occurred in the initial part of the cycle, to correctitself in time. The springs thus each reach the final part of the cycle, where they pass between the substantially parallelportions of the grinding faces, with straight spring-axis and with practically no compression, the substantially parallel portions giving an end feed dwell before discharge at 'a -spring length closely approximating the finished groundfree length. If grinding is finished with practically no compression of the springs before discharge, the springs have a squarer end than would otherwise be the case. Also, a disadvantage of the springs being discharged under a strong compression is that they may be 'damagedby' the edges of the grindingwheels. In order to obtain'the optimum conditions with the improved machine, theangularvposition of the grinding-whee1 axes and the speed of'the carrier member are chosen beforehand to suitithe gauge, diameter. and pitch of the particular springs which it is desired to grind.

The invention could apply to the grinding of other articles than springs, such articles being moved in succession between the grinding-wheels by means of a suitable movable carrier, such as the rotary pocketed carrier herein described.

I claim:

1. A machine for .grinding the ends of articles comprising two spaced-apart grinding wheels having opposed faces of convex conical form, said grinding wheels being mounted with their axes of rotation inclined to one another and substantially intersecting so that the conical faces of the wheels progressively approach one another from atapered article-receiving entrance at one side to a substantially parallel relation at the opposite side, in combination with means for driving said wheels each in the same direction, a rotary work carrier having openended article-receiving pockets arranged in circular succession, means for continuously rotating the work carrier, said Work carrier being mounted eccentrically to the grinding wheels for progressive rotary movement in the space between said grinding wheels so that opposite ends of the articles are caused to travel across and in continuous contact with the faces of the wheels in an arcuate path which is ofiset from the centers of the wheels and which extends from .a point at the said entrance side of the wheels'to a point where the wheel faces are in substantially parallel relation, the space between the wheels in said arcuate path continuously diminishing in depth between said points so that the rate of end grinding feed on the articles progressively decelerates from edge to edge of the wheels, terminating in a virtual dwell adjacent the said point Where the Wheels are substantially parallel.

2. A machine for grinding the ends of articles comprising two spaced-apart grinding wheels having opposed faces of convex conical form, said grinding wheels being mounted with their axes of rotation inclined to one another and substantially intersecting so that the conical faces of the wheels progressively approach one another from a tapered article-receiving entrance at one side to a substantially parallel relationat the opposite side, in

combination with means forndriving said wheels each.

in the same direction, a travelling work carrier having open-ended.articleq eceiving pockets arranged in succes-- sion, means for continuously driving the work carrier, said work carrier being mounted relative to the grinding wheels so as to move progressively between the grinding wheels in a line otfset from the axes of the wheels so that opposite ends of the-articles are caused to travel across and in continuous contactwith the faces of the wheels'in'a;path 'whiclrextendsfrom a'point at the said.

entrance side of the wheels to a point Where the wheel faces are in substantially parallel relation, the space between the Wheels in said path continuously diminishing in depth between said points so that the rate of end grinding feed on the articles progressively decelerates from edge to edge of the wheels, terminating in a virtual dwell adjacent the said point Where the dwells are substantially parallel.

References Cited in the file of this patent UNITED STATES PATENTS 1,210,937 Heim Jan. 2, 1917 6 Buck Mar. 15, 1921 Rodemeyer June 17, 1930 Wuerfel May 2, 1933 Happel July 25, 1933 Johnson Oct. 30, 1934 Holister et al. Apr. 8, 1947 Heath Ian. 1, 1952 Lowe Apr. 7, 1953 

